1. Field of the Invention
The present invention relates to a water-cooling jacket structure for an inspection hole of a flash furnace, and more particularly to a water-cooling jacket structure for an inspection hole of a flash furnace arranged at the periphery of a concentrate burner on a ceiling of a reaction shaft of the flash furnace used for inspecting and cleaning the inside of the furnace and the concentrate burner.
2. Description of the Related Art
First of all, an outline of the workflow of copper smelting will be explained. Ore dug out from a mine is called “crude ore”, and since it contains large amount of worthless materials (so called gangues) besides useful minerals, gangues are removed from the crude ore as tailings by a process called “concentration”, and the concentrates of high-grade obtained thereby are applied to smelting. The difference in physical or physicochemical property such as density, hardness, magnetism, permittivity and wettability of minerals is utilized in the concentration processes.
Concentrates obtained by concentration are thermally dried for the purpose of reducing heat energy required in smelting processes, making it easier to handle minerals in case of supplying and transporting them to furnaces, and also avoiding decrease in responsiveness due to moisture. Drying process is implemented, for example, by a rotary drier in a similar configuration as a rotary kiln provided with a furnace formed in a slightly inclined long cylindrical shape.
Concentrates obtained are supplied to a flash furnace with oxygen enriched air or hot air of high temperature simultaneously to induce instant chemical reaction, and separated into matte and slag. The flash furnace 1 is comprised of a reaction shaft 3, a settler 4 and an uptake 5, as shown in FIG. 5, and said reaction shaft 3 is provided with 1 to 3 concentrate burners 7. The concentrates are blown into the furnace via the concentrate burners 7. The flash furnace is characterized to be lower in specific fuel consumption than other means since it utilizes heat produced by oxidation reaction of the concentrates. However, in case the heat produced by oxidation reaction is insufficient, auxiliary combustions from the concentrate burners 7 using fuel oil and such can be implemented. In the matte obtained in this process, 60˜65% of copper is included. Since 1% of copper is included also in the slag, slag cleaning is conducted in a slag cleaning furnace 1a (not illustrated) to recover copper therein as matte to be further combined with matte obtained in the flash furnace 1 and processed in a converter. On a ceiling 3a of the reaction shaft 3 of the flash furnace 1, an inspection hole 9 for inspecting and cleaning the inside of the furnace and the concentrate burners is provided.
The converter is in the shape of a transversely-situated cylinder with its inner surface covered with magnesite or chrome-magnesite bricks, and configured so as to be inclined back and forth by an electric motor so that charging and discharging of materials can be conducted conveniently. A plurality of tuyeres is provided at the lower part of the sidewall of the furnace, and pressurized oxygen of about 100 kPa (1 kg/cm2) in gauge pressure is blown directly into the molten matte from the tuyeres. The operation includes slag-making stages and copper-making stages conducted in batches, and in the slag-making stage, steel included in the matte is removed as slag. The slag-making stage is repeated 2 to 3 times and after a certain amount of white metal is obtained in the operation, the operation proceeds to the copper-making stage to obtain crude copper. Crude copper obtained in the operation is then processed in a smelting furnace of transversely tilted type or reverberator type to adjust S and O included in the crude copper, to be cast into anode thereafter and to obtain electrolytic copper of higher grade by processing it with electrolytic smelting.
During the operation of the flash furnace, matte-sticking 2, so-called “beko” in Japanese, gradually builds up on the inner wall of the inspection hole 9 within the furnace and the concentrate burners 7. The matte-sticking can be a major problem to hinder inspection of the inner furnace and the concentrate burners 7 as it may grow as large as to block the inspection hole as well as air outlets of the concentrate burners 7. With an increasing demand for copper, the processing amount of copper in the operation of a flash furnace is increasing and the heat-load on the furnace is getting higher than before. Therefore, an increasing amount of matte-sticking 2 is adhered to some parts of the furnace, and the furnace has to be cleaned once in about every 4 hours (6 times per day).
Further, in order to reduce heat-load, the furnace body needs to be efficiently cooled. Here, reference is made to JP Patent Registration No. 3381241 and JP Patent Publication Heisei 5-180573. These references disclose structures to cool a furnace body by disposing cooling jacket plates or cooling boxes to surround the sidewall 3b of a reaction shaft.